Various types of dampers have been proposed for use in the fuel lines of internal combustion engines for reducing pressure pulsations in the fuel rail. A common form of such dampers includes a diaphragm which separates the fuel from a compressible damper chamber. The compressive characteristic of the damper chamber is typically achieved by filling the damper chamber with a compressible gas. The compressible gas is generally either atmospheric air that is trapped when the damper chamber is sealed or is a gas introduced into the damper chamber through a valve prior to sealing the valve. When gas is introduced into the damper chamber through a valve, pressurized gas can be used to produce superatmospheric pressure in the damping chamber. Having pressurized gas in the damper chamber enables the damper to more effectively damp larger pulsations which may occur in the fuel line. However, the need for a pressure valve complicates the design and structure of the damper, making the device more expensive to manufacture and more complicated to use. These and other disadvantages of the prior art are overcome by the present invention described below.